Updated

In the second attack in two days on an international mission in Libya, the International Committee of the Red Cross said its offices in the city of Misrata were rocked by a dawn explosion Tuesday that wounded the landowner's son and seriously damaged the building.

The attack came one day after the British ambassador's vehicle was attacked with rocket-propelled grenades in the eastern city of Benghazi. Two of the ambassador's bodyguards were injured in the Monday attack, according to Britain's Foreign Office.

Days earlier, a bomb went off just outside the U.S. consulate in Benghazi. No one was injured in that attack.

The attacks were reminders of how chaotic, insecure and fragmented Libya remains eight months after an armed rebellion toppled longtime dictator Moammar Gadhafi. The transitional leadership based in the capital of Tripoli has failed to impose its authority on much of the oil-rich North African nation. Instability has increased as cities, towns, regions, militias and tribes all act on their own, setting up independent and often conflicting power centers.

There are also concerns about the proliferation of thousands of weapons, including rockets, machine guns and rocket-propelled grenades in Libya in the aftermath of the civil war last year.

Tuesday's explosion at the Red Cross building in Misrata, Libya's third-largest city, was the second time the body has come under attack. In May its offices in Benghazi were attacked by RPGs.

Red Cross spokeswoman Beltifa Soumaya said investigators are looking into who was behind the attack. She said the Red Cross, with four offices in Libya, has had a presence in the country since February, 2011, to assist refugees and those in need of aid after the country's civil war.

A Libyan jihadist group claimed responsibility for the attack on the U.S. consulate and for the May attack on the offices of the Red Cross in Benghazi.

The group, calling itself "Brigades of imprisoned Sheikh Omar Abdel-Rahman" posted a message on jihadist forums in late May saying the Red Cross in Benghazi was a target as "one of the strongholds of Christian missionary activity."

According to the SITE monitoring group, the brigade later released a three-minute video of the attack, showing a fighter preparing the RPG and firing it at the building at night.

It also released a statement on Monday, saying the attack on the U.S. consulate was a response to the drone strike that killed al-Qaida's second-in-command Abu Yahya al-Libi in North Waziristan, Pakistan, on June 4 and to U.S. drones flying in Libyan skies.

NATO halted its airborne missions over Libya with the end of the civil war last year.

The group is named after the blind Egyptian cleric who is serving a life sentence in the U.S. and was the spiritual leader of men convicted in the 1993 World Trade Center bombing.

It was not possible to verify the authenticity of the claims, and the group had not been heard from before.